The Inspection And Measurement Work Can Be Performed Using The Pressure Gauge - Skoda Citigo 2012 Workshop Manual

Citigo 2012 ➤ , Fabia 2000 ➤ , Fabia II 2007 ➤ , Fabia II 2009 ➤ , Fab ...
Air conditioning system with refrigerant R134a - Edition 10.2014
2.6 The inspection and measurement work
can be performed using the pressure
gauge
Readout on the pressure gauge
1 - Temperature scale for refrigerant R134a CF3–CH2F or
CH2F–CF3
2 - Pressure scale
The pressure gauges can have one or more temperature scales
in addition to the pressure scale. The values of the scale for
R134a are assigned to the relevant vapour pressure table.
As various refrigerants build up different vapour pressures at the
same temperature, every temperature scale is marked for the
corresponding refrigerant.
⇒ "2.6.1 Pressure gauges allow to carry out the following inspec‐
tion and measurement work", page 30
2.6.1 Pressure gauges allow to carry out the
following inspection and measurement
work
Pressure and temperature measurement on the refrigerant circuit
♦ The high-pressure manometer measures the pressure and the
temperature, which spreads evenly from the outlet of the AC
compressor via the condenser up to the constriction (throttle
or expansion valve) when the AC compressor is switched on.
♦ The low-pressure manometer measures the pressure and the
temperature, which spreads evenly from the constriction
(throttle or expansion valve) via the evaporator up to the inlet
of the AC compressor.
Note
The interdependence described on the pressure gauges, be‐
tween pressure and temperature, only exists where liquid or
vapour is contained in the refrigerant circuit, however not gas. In
the gaseous condition, the temperature is around 10 °C to 30 °C
higher than the pressure gauge indicates.
Evidence of refrigerants in a closed reservoir
In a closed reservoir or in the refrigerant circuit, the refrigerant
R134a is present if the temperature reading of the pressure gauge
corresponds to the temperature of the refrigerant (liquid is at am‐
bient temperature).
A closed reservoir or a switched off refrigerant circuit is empty if
the temperature reading of the pressure gauge lies below the
temperature of the refrigerant.
Note
The interdependence described on the pressure gauges, be‐
tween pressure and temperature, does no longer exist if no liquid
is contained and the pressure only builds up through gas.
30
Rep. gr.00 - Technical data